Coated Urea Fertilizer Research Articles

Acetylated lignin sulfonate as a biodegradable coating for controlled-release urea fertilizer: A novel acetylation method and diffusion coefficient analysis

Plants require essential nutrients to grow, which soil alone cannot provide. Chemical fertilizers like urea supply the necessary nutrients, including nitrogen. They quickly dissolve in water and can contaminate it with nitrate and nitrite, which can cause diseases. Slow-release fertilizers are a better option to reduce environmental risks. Researchers are exploring cheap and biodegradable alternatives, such as lignin. A critical discussion in the coated urea fertilizer is modeling the nitrogen diffusion process in the coating, which predicts the system's behavior. This article uses lignin sulfonate to coat urea fertilizer, which should first be acetylated with decanoyl chloride. One of the critical parameters is the diffusion coefficient (D). D is determined using the mass transfer flux and the completion time of the effective substance, and with its help, the graph of the total mass transferred from the membrane in a specific time (Mt) is determined. D equals 6.298813 × 10−8 cm2/s using the time lag method. Also, with the fixed-point convergence method, 5.8849 × 10−8 cm2/s was obtained, which has about 0.80 % error with the D obtained by the time lag method. The Mt obtained from the analytical method and the experimental data coincides with a minimal error, which indicates high accuracy.

Dual inhibitors for mitigating greenhouse gas emissions and ammonia volatilization in rice for enhancing environmental sustainability

The use of inhibitors retain nitrogen as ammonium in soil, giving plants ample time for its uptake. This can reduce nitrous oxide (N2O) emissions, but extended retention may increase ammonia (NH3) volatilization. This study assessed the efficacy of coated urea fertilizers in reducing greenhouse gas (GHG) emissions and NH3 volatilization in rice fields. A field experiment with Pusa 44 rice in the kharif seasons of 2019 and 2020 compared unfertilized control (No N), prilled urea (PU), nitrification inhibitors (NIs): neem oil-coated urea (NCU), karanj oil-coated urea, and dual inhibitor (DI: Limus + NCU). The coated urea fertilizers were analysed with scanning electron microscopy, fourier transform infrared spectrometry, and energy-dispersive spectroscopy. Compared to PU, DI reduced N2O emissions by 23.7%, methane by 11.9%, and NH3 by 29.8%. DI also reduced NH3 emissions by 36–39% compared to other NIs. Overall, DI can lower the global warming potential of rice cultivation in trans Indo-Gangetic plains region by 17.1% for both direct and indirect emissions, suggesting its significant potential to reduce India's contribution to total agricultural GHG emissions.

Assessing the Impact of Coated and Prilled Urea Fertilizers on Nitrogen Dynamics and Fodder Maize Yield in Alfisols

The study investigates the impact of different urea fertilizers on nitrogen mineralization, leaching losses, and growth, yield of fodder maize in Alfisols. Nitrogen is vital for plant growth but deficient in soils. Urea, a widespread nitrogen fertilizer, suffers from significant losses, prompting the development of controlled-release urea (CRU) fertilizers. This study assesses various urea formulations with coated urea and prilled urea. Laboratory incubation studies show that coated urea exhibits slower NH4+-N release, reducing losses and improving efficiency compared to uncoated urea. Nitrate content increases steadily periodically with coated urea, potentially enhancing nitrogen availability to plants. Greenhouse experiments reveal significant differences in plant height, leaf number, and leaf area among treatments. Coated urea formulations, chiefly CSPC @3%, demonstrate superior growth parameters (plant height-169.56cm, number of leaves-10.33 and leaf area-1850.59), yield (green fodder-328.25 gplant-1, dry fodder-198.61 gplant-1 and dry matter percentage-54.52) and quality parameters (crude protein-4.03, total ash content-3.82%) compared to prilled urea growth parameters (plant height-113.38cm, number of leaves-8.07 and leaf area-1670.98), yield (green fodder-246.26 gplant-1, dry fodder-116.35 gplant-1 and dry matter percentage-44.32) and quality parameters (crude protein-2.88, total ash content-2.75%), likely due to sustained nitrogen release. Higher nitrogen availability from coated urea leads to increased forage yield and quality. The findings suggest that coated urea fertilizers, specially CSPC @3% advocate improved nitrogen management, enhancing fodder maize productivity and sustainability.

Enhancing the use of coated urea fertilizer and assessing its effect on growth and yield performance in grain corn

Use of urea fertilizer is currently increasing to meet the agricultural demand. However, the efficiency and optimization of urea application in agriculture is uncertain. Therefore, this study was conducted to compare the efficacy of slow-release urea and standard urea fertilizer. Reductions in the N rate of the slow release was assessed by measuring the different growth performance and yield at the field. A 25% reduction in N content using coated urea gave similar growth performance and yield compared to standard practice The findings indicated that there was no significant difference in stem diameter, number of leaves and chlorophyll content between the control treatment and slow-release urea. Grain yield and yield components like cob length, number of grains per cob, weight of grain per cob and 1000 grain weight obtained in the field was similar when applying the slow-release urea with the yield and yield components obtained from standard practice as a control. We conclude that this slow-release urea can be used in extensive cropping of corn while promising at least the same yields than standard practices with reducing impact on environment and nitrogen losses in the soil.

EVALUASI PUPUK NITROGEN LEPAS LAMBAT PADA TANAMAN JAGUNG (Zea mays L.)

Slow-release fertilizer can provide nutrients more efficiently; nutrients are released and available slowly so that they have the potential to be absorbed by plants. This study aimed to investigate the effects of several slow-release N fertilizers on the growth and yield of corn (Zea mays L.) in sandy soil. This research was carried out in the greenhouse and laboratory of the Faculty of Agriculture, University of Trunojoyo Madura. The experiment was arranged on a non-factorial completely randomized design. There were six treatment levels, namely P0 (uncoated urea fertilizer, applied into one application), P1 (uncoated urea fertilizer, split into three times applications), P2 (urea fertilizer with bentonite coating, P3 (urea fertilizer with biochar coating), P4 (urea fertilizer with coal coating), and P5 (urea fertilizer with biochar compost coating). All coated urea fertilizers were applied one time at the early growth of corn. The results showed that the application of slow-release N fertilizer had no significant effect on plant height, number of leaves, leaf area, cob length, diameter, plant fresh weight, plant dry weight, seed weight per plant, 100 seed weight, and flower age. However, the application of slow-release N fertilizer had a very significant effect on plant height at 42 DAP, the number of leaves at 14 DAP and 56 DAP, and leaf area at 28 DAP and 56 DAP. All coated urea fertilizers were as effective as uncoated urea on the growth and yield of corn.

The Effects of Long-Term Application of Stabilized and Coated Urea on Soil Chemical Properties, Microbial Community Structure, and Functional Genes in Paddy Fields

The addition of fertilizers is indispensable in agricultural production, and currently, there is a wide variety of new types of fertilizers available. For example, commonly used are stabilized fertilizers with inhibitors and coated slow-release fertilizers, among others. However, the long-term effects of these fertilizers, when applied continuously are still uncertain. This study will provide scientific and theoretical support for the development and promotion of these fertilizers. A 16-year paddy field with brown soil treated with different urease and nitrification inhibitors, sulfur-coated urea (SCU), and resin-coated urea (PCU) was studied. The study showed that long-term use of conventional urea nitrogen fertilizer resulted in a significant reduction in soil total phosphorus (TP). Long-term application of NBPT and conventional urea significantly increased soil organic matter (SOM). Moreover, except for HQ and NBPT+DMPP, the prolonged application of new urea fertilizers also significantly enhanced soil total potassium (TK). Application of SCU fertilizer in brown soil type paddy fields resulted in a significant decrease in soil pH over time. However, changes in pH had no effect on the abundance of ammonia-oxidizing bacteria (AOB), as AOB was mainly affected by soil-available N. DMPP, HQ+DCD, NBPT+DMPP, SCU, and PCU significantly reduced the 16S rRNA gene copy number of soil bacteria, with the greatest effect of coated urea fertilizer (SCU and PCU). Long-term application of stable urea fertilizer with HQ significantly reduced the bacterial community in paddy soil. Conversely, HQ+DCD-stabilizede urea fertilizer significantly increased the population structure and abundance of Basidiomycota fungi while decreasing the population structure and abundance of Rozellomycota fungi. DMPP-stabilized urea fertilizer notably increased the population structure and abundance of Ascomycota fungi while decreasing the population structure and abundance of Rozellomycota and Chytridiomycota fungi. Furthermore, HQ-stabilized urea fertilizer significantly reduced the population structure and abundance of Chytridiomycota fungi.

Using Packaging Technology to Reduce the Fragmentation of the Added Fertilizer, Improve Growth and Increase Yield Efficiency for Varieties of Forage Barley

The experiment was carried out in one of the farmers’ fields in Muthanna Governorate, Rumaitha district, which is 25 km from the city center and for the agricultural season 2021-2022, with the aim of achieving the maximum possible benefit from the added nitrogen fertilizer (T1, T2 and T3) in addition to the treatment of comparison with ordinary urea (T4), which was added according to the recommendation of fertilizer and the possibility of reducing the infusions of its addition Their reflections in nitrogen absorption, improving plant growth and increasing plant yield in quantity and quality, for four different varieties (Samir, Burqa, Aba99, and Aba 265) of the feed barley crop, were applied according to the design of the complete random sectors (RCBD) with three repeaters. The results showed that the preliminary results for the highest averages amounted to 43.680 and 10.545 tons, and 7.80 and 8.41% for the cultivars. It reached 8.64%. Either the coated urea fertilizer fractional coefficients, the retail transaction in two batches (T2) significantly exceeded the total green and dry feed yields, with averages of 45.380 and 11.315 tons E-1 respectively, when overlapping between the two factors a discrepancy between the combinations within the overlap was observed and the combination between the two classes A265 and A99 with the retail transaction in two batches (T2) by recording the highest average of the total green and dry feed yield amounted to 52.170 and 12.077 tons E-1 for the two varieties in succession.

IMPACTS OF CLIMATE CHANGE, FORMS, AND EXCESS OF NITROGEN FERTILIZERS ON THE DEVELOPMENT OF WHEAT FUNGAL DISEASES

Background. Global climate change and excessive nitrogen application has become a significant issue and inevitably threatens sustainable wheat production, not only with direct negative effects on crop growth but also with profound impacts on biology and pest and disease management.
 Purpose. This review addresses the current challenges, namely the negative effects of climate change and the forms and excess of nitrogen-rich fertilizers on the development of fungal diseases in wheat, as well as management strategies.
 Materials and methods. To achieve the stated objective of the study, the scientific literature published during the last 20 years on the impacts of climate change and the forms and excesses of nitrogen fertilizers on the development of fungal diseases and on the yield of wheat were reviewed.
 Results. Thus, in mitigating these challenges, it is necessary to optimize the dose of nitrogen fertilizers, apply nitrogen in the form of nitrate, ammonium sulphate, ammonium nitrate, and coated urea fertilizers, to use silicate fertilizers such as calcium, magnesium, and potassium silicate, and to perform a long rotation of wheat through perennial legumes and leguminous crops, as well as to develop, through genome editing, varieties with high yield potential, resistant to biotic and abiotic stresses, and of good end-use quality, or plant new cereals that have needs for heat and a longer reproductive growth period.
 Conclusion. To develop an effective agricultural management strategy, future research should be based on the study of the interactions among crops, pests, pathogens and farming system under climate change, taking into account all parameters such as temperature increase and CO2, extreme precipitation, etc. A sufficient number of results must be published to be able to draw meaningful conclusions.

Lignin nanoparticles filled chitosan/polyvinyl alcohol polymer blend as a coating material of urea with a slow‐release property

AbstractThe present study aims to develop a novel waterborne chitosan‐based coating formulation for slow‐release urea fertilizer. Coating formulations were elaborated by blending chitosan (Cs) and polyvinyl alcohol (PVA) (50/50, wt/wt) followed by the addition of lignin nanoparticles (LNPs) at various loadings (1, 2, 3, and 5 wt% LNPs) to yield viscous coating formulations. Formulations were cast to obtain coating films on which several structural, thermal, morphological, mechanical, and physicochemical characterizations were performed. Results showed that the Cs/PVA‐LNPs (3%) formulation exhibited suitable physicochemical characteristics in terms of the hydrophobic–hydrophilic balance, reduced water vapor permeability, and tolerated elasticity making it suitable to be used for fertilizer coating. Urea granules were coated by Cs/PVA and Cs/PVA‐LNPs formulations under controlled spraying and drying conditions until a good adhesion between the fertilizer and coating was obtained. Coated granules showed a good slow‐release N property over time and results indicated that the incorporation of LNPs was beneficial since its prolonged the longevity of the coated urea fertilizer up to 18 days compared to 5 days for the neat Cs/PVA. Hence, the proposed nanocomposite system showed great potential to be used as a coating material to produce a new slow‐release N fertilizer for sustainable crop production.

COMPARATIVE EFFECTS OF DIFFERENT RATES OF NEEM OIL COATED AND UNCOATED UREA ON THE GROWTH AND YIELD PARAMETERS OF RICE

Application of neem oil coated urea fertilizer is more effective in improving the growth and yield of cereals in a nutrient depleted soil compared to uncoated urea. Two (dry and rainy) seasons experiment was carried out at two locations of the Ambrose Alli University Teaching and Research Farm (Emaudo and Ujemen). The experiment was laid out in a Radomized Complete Block Design (RCBD) with eleven treatments replicated three times. The pre- planting soil testing was conducted in a laboratory and the results showed that the soil was deficient of essential nutrients and required fertilizer application. Neem oil coated and uncoated urea fertilizers were applied at different rates to soil on which rice the test crop was planted. The application of neem oil coated urea significantly (p< 0.05) increased the number of tillers, panicles and yield of rice compared the uncoated urea and control treatment. At Emaudo experimental site, the application of 100 % TD N by NOCU@ 1.25 L/Mt to rice was 40%, 41% and 64% higher than the granular urea, inhibitor and the control. Also, at Ujemen experiment site, the grain yield from the application of 100 % TD N by NOCU@ 1.25 L/Mt to rice was 34%, 32% and 66% higher than the granular urea, inhibitor and the control respectively. During the dry and rainy seasons at both locations the application of 100 % TD N by NOCU@ 1.25 L/Mt significantly (p< 0.05) increased the growth and yield of rice compared to other treatments, it is therefore recommended for farmers.

Effects of nano zeolite-coated fertilizer and cow boneon the growth and N uptake of maize in inceptisol of Patuk, Gunung Kidul

Nanotechnology is a science that deals with objects measuring 1-100 nm that are different from their original properties. Nano-technology fertilizers are more reactive and on target with minimum use. Nanotechnology fertilizers can be utilized as slow-release fertilizers, allowing for optimum fertilizer uptake by plants. Because of the holes that can store nitrogen fertilizers, zeolite and bovine bone can be utilized as fertilizer coatings. This study was conducted at Universitas Gadjah Mada's Faculty of Agriculture. The research method used was a 2X5 factorial completely randomized design (CRD) with each treatment being repeated 3 times so that the total polybags used were 30 polybags. The first factor was the type of coating material for urea, nano zeolite, and nano bovine bone. The second factor consisted of a dose of coated urea fertilizer with five kinds of dose treatments, which were 0, 100, 200, 300, and 400kg.ha-1. ANOVA was used to analyze parameter data, followed by testing using the DMRT (Duncan's Multiple Range Test). When compared to nano bovine bone, the effectiveness of N removal with nano zeolite generated the best results as a slow-release fertilizer on N uptake. The best N fertilization dose with nano zeolite coating was 200 kg.ha-1, which increased corn plant growth by producing the highest plant height (167.17 cm) and N uptake of 1.6 g/plant. This research can be a recommendation for more effective and efficient Nitrogen fertilization for corn farmers.

Controllable release fertilizer with low coating content enabled by superhydrophobic castor oil-based polyurethane nanocomposites prepared through a one-step synthetic strategy

Although the inherent degradability and sustainability of bio-based polymers make them promising coating candidates for controlled-release fertilizer (CRFs), large amounts of coating materials (coating content usually above 5%) and complex modification process are usually required to achieve controllable-release characteristics, which increases the production costs and therefore limits their application. In this study, superhydrophobic castor oil-based polyurethane/carbon black nanocomposites was developed through a one-step synthetic strategy to synthesize CRFs with low coating content by a three-layer rotating-drum coating method. The effect of the carbon black content and layer distribution on contact angles, physicochemical properties, microstructure, and release characteristics of the resulting coating material and CRFs was characterized and discussed. The contact angle of the polyurethane nanocomposites can reach up to 152.6°. In addition, the N release longevity of the coated urea fertilizer was extended to 30 days, definitely meeting the standards for CRFs using low coating content of 3 %. The coated fertilizers presented Super Case II transport mechanism. The mechanism underlying the controlled-release of this coated fertilizer was explored and discussed. The technique reported here offers a number of advantages, including low cost, easy performance, and excellent controllable-release performance, opening numerous opportunities for widely application of this environmentally-friendly, green CRF.

Role of zinc-coated urea fertilizers in improving nitrogen use efficiency, soil nutritional status, and nutrient use efficiency of test crops

The rise in global population, urbanization, and desertification pushes the farming community toward intensive cropping to meet the augmented food demands with consequent exhaustion of soil’s nutritional status and fertility. In recent times, environmental pollution and cost of crop production have been enhanced due to excessive and inefficient use of nitrogenous fertilizers. As an abatement strategy, seven different coated urea fertilizers, namely, gelatin-coated (G), zinc oxide with gelatin-coated (ZnOG), zinc oxide-coated (ZnO), sonicated zinc oxide-coated (ZnO-Son), zinc oxide with molasses-coated (ZnOM), zinc sulfate with molasses-coated (ZnSM), and zinc sulfate-coated (ZnS) were prepared in a fluidized bed coater. The coated samples were characterized through XRD, SEM, and FTIR techniques, while a crushing strength test was carried out to assess the impact of inventory operations on physical integrity of coated prills. Pot tests with ryegrass (Lolium perenne) as a test crop were carried out to evaluate the effect of coated urea fertilizers on yield and nitrogen (N) and zinc uptake in order to enhance nitrogen use efficiency and reduce pollution. Our results suggest that the affinity between urea surface and coating materials was of physical nature. All zinc oxide- or gelatin-coated treatments significantly increased the dry matter yield, nitrogen uptake, apparent nitrogen recovery (ANR), zinc uptake, and apparent zinc recovery (AZnR). ZnOG was proved to be the best sample in terms of balancing soil chemical properties with improved soil nutrition and producing best with plant yield (94% higher than UC), N uptake (75% higher than UC), Zn uptake (450% higher than UC), and nitrogen use efficiency (48 vs. 23% for UC). Our results suggest that the use of such coated fertilizers can lead to improve yields, nutritional values of crops, and overall agro-ecological scenario.

Efficacy of neem and zinc coated urea on productivity and economics of wheat (Triticum aestivum)

Nitrogen (N) fertilizer-use efficiency (20 − 50%) is low in wheat fields in India. Coated urea can increase N-use efficiency in wheat, but a desirable coating for use with urea is not widely accepted yet. Therefore, to study the efficacy of coated urea on productivity and economics of wheat, an experiment was conducted at Research Farm of SKUAST-J, India, during winter season of 2017 − 2018 and 2018 − 2019. The experiment was laid out in a randomized block design with 11 treatment combinations, replicated thrice. The treatments comprised of various doses of different types of coated urea viz prilled urea, Neem coated urea (NCU), Zinc coated urea (ZnCU), and Neem + Zinc coated urea (NCU + ZnCU). Different doses of coated urea fertilizers showed significant effect on the growth, yield, economics, and nutrient uptake of wheat crop. Application of 100% of recommended (Rec.) nitrogen (N) through ZnCU + Rec. Phosphorus (P), Potassium (K) and Zinc (Zn) (T8) showed significantly better growth, yield attributing characters and grain and straw yield, during both the years of study and remained statistically at par with the application of 85% of Rec. N through ZnCU + Rec. P, K, & Zn (T7), 100% of Rec. N through NCU + ZnCU + Rec. P, K, & Zn (T11), 85% of Rec. N through NCU + ZnCU + Rec. P, K, & Zn(T10) and 100% of Rec. N through NCU + Rec. P, K, & Zn (T5).Similarly, nutrient uptake (N, K and Zn), net returns, and B:C ratio were also observed to be significantly higher with the application of 100% of Rec. N through ZnCU + Rec. P, K, & Zn than other treatments. However, maximum mean Agronomic use efficiency (AUE) and Recovery use efficiency (RUE) of 36.2% and 30.0%, respectively, were found with the application of 85% of Rec. N through ZnCU + Rec. P, K, & Zn (T7) over the application of100% of Rec. N through urea + Rec. P, K, & Zn(T2).

Comparative Effect of Various Organic Extracts Coated Urea Fertilizer on the Release Pattern of Ammonium and Nitrate in the Soil at Different Time Intervals

The losses of nitrogen (N) fertilizer applied to the soil microenvironment reduce its efficiency. Different strategies like the use of polymer coating and chemical nitrification inhibitors had been employed to reduce N losses. But these chemical nitrification inhibitors are very expensive. Thus, a study was conducted to investigate the effects of different concentrations of Parthenium extract, neem oil, and acidulated cow dung compost extract on N dynamics in the soil. Three concentrations of Parthenium extract (5, 10, and 15%) and neem oil (1, 2, and 3%) were coated on urea granules using a polymer as the binding agent. Three pH (2, 4, and 6 pH) based acidulated cow dung compost extracts were also coated on urea granules in the same pattern. These coated fertilizers and uncoated urea were applied in jars filled with soil (100 g per jar) at the rate of 1 g of fertilizer per jar. One treatment was kept as control (without fertilizer). Treatments along three replications were arranged according to the completely randomized design. Results depicted that all coating materials caused the release of N consistently from applied fertilizers compared to uncoated treatment. In addition, percent nitrified N was also reduced significantly in coated treatments in comparison to the uncoated urea and control treatments. However, the level of concentration effect was not obvious as lower concentrations of these extracts and oil also performed almost equal to that of higher concentrations in inhibiting nitrification process.

Evaluation of late‐season nitrogen source application on autumn color and winter injury of ‘Riviera’ bermudagrass in the upper transition zone of the United States

AbstractLate summer and autumn application of nitrogen (N) to bermudagrass (Cynodon spp.) in the transition zone has been associated with enhanced turfgrass color but has been thought to increase the potential for winter injury. Eleven N sources were applied in late summer and early autumn to provide a total annual N level of 98 kg ha−1 in Olathe, KS to evaluate fall color and spring green coverage of ‘Riviera’ bermudagrass [Cynodon dactylon (L.) Pers.]. Treatments included experimental coated urea fertilizers, N sources containing urease inhibitors, urea, and nontreated turfgrass. Significant winter injury occurred throughout the experimental area. Turfgrass color in late October was positively correlated with green coverage evaluated in May (r = .55; P < .001). For example, bermudagrass treated with AND3.0EX (Poly/Humic Coated Urea) had a color rating of 3.5 (1 to 9 scale; 9 = dark green) in late October, and green coverage in May was 44%. Nontreated turfgrass had a color rating of 1.5 in late October, and green coverage in May was 8%. Enhanced winter survival of bermudagrass following late‐season N application may require that turfgrass managers rethink traditional N programs limiting application to only late spring and midsummer dates in the transition zone.

Coating of urea granules with epoxidised vegetable oil cured by triethylenetetramine for control release: A green approach

The manuscript represents epoxidation of linseed oil to be coated on urea granules for their control release. Linseed oil was epoxidized in the presence of acetic acid and hydrogen peroxide. Structural transformation of unsaturated oil to epoxy group was confirmed by FTIR and end group analysis. Thereafter, the epoxidized linseed oil (ELO) was coated on the surface of urea granules and crosslinked subsequently using triethylenetetramine (TETA) a renewable substrate. Coated urea as an essential release component was first characterized for coating using optical microscope and SEM images. The control release behaviour of the prepared coated urea fertilizer was studied using dissolution and release urea from the crosslinked structure. The results demonstrated fast dissolution of pristine urea that is responsible for unwanted losses, toxicity, and harmfulness to environment, while coated with ELO and crosslinked with TETA required more time as necessary for slow and control release. The results demonstrated epoxidized oil as a green solution to coat urea granules for its control release.

Influence of Biodegradable Polymer Coated Urea on Nitrogen Uptake and Utilization of Maize (Zea mays L)

Controlled release nitrogen fertilizers could be an excellent management approach for improving nitrogen fertilizer efficiency. The present study aimed to investigate the effect of coated urea fertilizers to increase nitrogen uptake and utilization of maize. The nitrogen use efficiency of maize from various biodegradable polymer-coated urea fertilizers, such as palm stearin coated urea (PSCU), pine oleoresin coated urea (POCU), and humic acid coated urea (HACU), was determined in a pot culture experiment conducted at the Department of Soil Science and Agricultural Chemistry, Tamil Nadu Agricultural University, Coimbatore, during 2021. The coating materials have been coated on urea with different coating thicknesses, viz., PSCU - 5, 10, 15%, POCU – 2, 4, 6%, and HACU - 5, 10, 15%. Among all the treatments, T11: HACU 15% produced highest grain yield (72.0g plant-1) followed by T7: POCU 4% (69.7 g plant-1) and T4: PSCU 10% (69.0g plant-1). In terms of dry matter production, T10: PSCU 10% produced maximum dry matter (186.5g plant-1), followed by T11: HACU 15% (186.2 g plant-1), and T7: POCU 4% (185.3g plant-1). The nitrogen uptake by the maize plant was higher in T7: POCU 4 % (1.62g plant-1), followed by T11: HACU 15% (1.59 g plant-1) and T4: PSCU 10% (1.59g plant-1). Irrespective of treatments, the highest nitrogen utilization by the maize crop was found in T7: POCU 4% (73.9%) followed by T4: PSCU 10% (71.1%) and T11: HACU 15% (70.9%) treatments. When compared to uncoated urea fertilizer, all coated urea fertilizers outperformed uncoated urea fertilizer in terms of grain yield, dry matter accumulation, and nitrogen uptake. To improve the nitrogen use efficiency, coated urea fertilizers prove to be a promising alternative to uncoated urea fertilizers.

Effect of biodegradable polymer coated urea fertilizers for the growth and yield of hybrid maize (Zea mays L.)

Urea is an instantaneous fertilizer, releasing nitrogen (N) rapidly after application to soil as it is effectively lost as ammonia volatilization and nitrate leaching which causes nitrogen inadequacy around roots and in the long run causes a deficiency between nitrogen demand and supply. The nitrogen from controlled-release urea can be consumed by crops more congenial than the nitrogen from uncoated urea. A pot culture experiment was carried out to investigate the response of maize crop to controlled-release urea fertilizers. Three different coated materials were utilized to coat on urea viz., palm stearin, pine oleoresin, humic acid. Different thicknesses of coated urea were developed such as palm stearin coated urea (PSCU) 5, 10, 15%, pine oleoresin coated urea (POCU) 2, 4, 6%, and humic acid coated urea (HACU) 5, 10, 15%. The coated urea fertilizers impacted the growth and yield of maize and increment the yield from 26.7 – 33.5% over the uncoated urea. The most noteworthy rate augmentation of yield was seen in HACU 15% (33.5%) trailed by POCU 4% (32.4%) and PSCU 10% (32.1%). It was inferred that, better synchronization between the nitrogen Release from coated urea fertilizers and growth of maize throughout the growing season.

Reducing nitrate leaching losses from turfgrass fertilization of residential lawns.

Fertilizer applications on lawns have raised environmental concerns in many Canadian municipalities. In this greenhouse study, NO3 -N leaching losses from Kentucky bluegrass (Poa pratensis L.) lawns were evaluated on two soils (a schist loam and a clay loam) and on a sand/peat moss rootzone mix (80% sand, 20% peat moss). Eight different fertilizer N sources (urea, Polyon 8 and 12-wk release, Duration 45 and 90-d release, XCU, corn gluten meal, and UFLEXX) were assessed at five application rates (25-200kg N ha-1 yr-1 ) and two application frequencies over two 8-wk trials. Average NO3 -N concentration in leachate were measured at levels of 3.5, 7.4, and 1.4mg L-1 from turf grown in loam, clay, and sand respectively, but losses from loam and clay were mostly affected by N mineralization from organic matter. Turf fertilized with rates ≥100kg N ha-1 generally resulted in acceptable visual quality on both soils, but coated-urea fertilizers were more efficient to reduce leaching. In sand, UFLEXX and urea (150 and 200kg N ha-1 ) as well as XCU (200kg N ha-1 ) resulted in higher NO3 -N losses, varying from 8.5 to 23.7mg L-1 , and losses from other N sources were consistently below 3mg L-1 . Our results show that it is possible to maintain good quality turfgrass while keeping low NO3 -N leaching losses (i.e., <4mg L-1 ) in loam, clay, and sand by selecting the ideal combination of N source, N rate, and application frequency.